Arrange a rack in the middle of the oven and heat to 400°F.
Remove the whole tomatoes from the cans (keeping the juice aside) and lay them out in a single layer on a rimmed baking sheet, scatter the garlic bits over the tomatoes and drizzle with 1/4 c of the oil; roast until soft and caramelized/brown on the bottom, about 30 minutes.
Meanwhile, heat the remaining 1/4 cup of oil in a large soup pot over medium-high heat; add the onion and sauté for about 5 minutes. Add the tomato paste and stir around until the paste has deepened in color, about 2 more minutes.
When the tomatoes are ready, transfer them, along with all the garlic and oil to the pot; add the reserved tomato juice in the cans and the broth. Stir to combine and bring to a boil. Reduce the heat to maintain a gentle simmer, cover the pot, and simmer 5 minutes.
Purée the soup in batches in a stand blender or with an immersion blender until smooth. Season with salt and pepper as needed and heat for another 5 minutes.
In a small bowl, mix ricotta, parsley, salt, pepper and 1 tbsp olive oil.
Ladle soup into bowls and spoon a dollop of the ricotta onto each bowl and swirl with extra olive oil if desired.
Serve warm (remainder can be refrigerated or frozen).